This article describes ways of taking advantage of structured wiring for whole house music distribution system. It explores the problems and opportunities with structured wiring and offers solutions for whole house audio distribution. A brief review of the benefits and advantages of these novel solutions are also explained.

Taking advantage of structured wiring for whole house music distribution system

This article describes
ways of taking advantage of structured wiring for whole house music
distribution system. It explores the problems and opportunities with
structured wiring and offers solutions for whole house audio
distribution. A brief review of the benefits and advantages of these
novel solutions are also explained.

Over the last five years or more, many home builders have adopted various
standards of structured wiring to make these homes future-proofed. Their answer
to future proofing has been a bundle of wires homerun to a central location from
various rooms in the house. Typically a couple of coaxial cables such as the RG6
or RG59, and a couple of category 5 cables are used in the bundle. Sometimes a
couple of multi-mode glass fiber-optic cables are also included to assure the
customers that the wiring is truly future-proofed! The basic usage of the
coaxial cables is for antenna TV or CATV signal distribution to various rooms
from the head-end unit. The other coaxial cable is presumed to future-proof the
house for sending security camera or other channel modulated video signals to
the head-end for combining with the TV or CATV signals and re-distribution
around the house. In almost all cases, one of the category 5 cable is used for a
standard telephone line distribution to all the rooms. The other category 5
cable is presumed for computer networking or a local area network (LAN) in the
home. Almost 100% of the fiber optic cables that have been wired in these homes
are there still sitting idle and presumably will be unused for the foreseeable
future.

Unfortunately, very little attention has been paid to whole house music
distribution in these industry standard structured wiring systems. Part of the
problem has been lack of understanding on the builder community for what is
really needed for distributed music system, as well as the substantial
additional expenses for pre-wiring homes with the archaic speaker wire runs.
Interested readers are referred to earlier articles by the author ( MultiRoom
Audio on Cat5 / Whole
House A/V)
published in 2001 to understand the problems and inefficiencies of
speaker wire based distributed music systems. So most structured wiring homes
are incapable of distributed music system without expensive and major retrofit
for a traditional speaker run.

Luckily for the home-owners, there are a couple of options. The first is to free
up at least one category 5 cable in the structured wiring system. This is very
easy by using either a 900 MHz or 2.4 GHz cordless telephone system that
supports multiple hand-sets. The prices on the cordless phones have dropped
significantly in the last five years to accommodate the usage. Also for those
with multiple computers in the home, wireless networking with 802.11b or 802.11a
may also make sense as the prices on these devices mature. This could free up
another category 5 cable as well I the future. In the following section, a
couple of systems are presented that would allow whole house distributed music
system on these category 5 cables.

The system design

The first system addresses a basic whole house music system. It allows the
user to take a music signal from an integrated receiver, a CD juke-box, a hard
disk based audio server or even an MP3 player from a PC, and distribute it
throughout the house on the category 5 cable of the existing structured wiring
system. There are a few products on the market now that facilitate this but
Figure 1 shows a very pragmatic solution based on patent pending PADS™
(Pragmatic Audio Distribution System). A PADS™ sender is housed in a single
gang box that is located at the structured wiring end of the category 5 cable in
the family room. The line level audio signal from the source is then sent on the
category 5 cable to the central connection point in the closet. The PADS™
distribution unit receives this signal on the category 5 cable and redistributes
it to four other rooms along with power for the in-wall amplifiers on the
structured wiring category 5 cables. In the remote rooms, housed in single gang
box is the volume control unit and high performance audio amplifiers that
receive the signals and power to drive the floor standing or in-wall speakers.
The PADS™ units deliver 24 watts per channel in each room with a 20Hz to 20KHz
frequency response, a better than 100 dB signal to noise ratio and 100 dB
dynamic range at the end of 300 ft. of category 5 cables. For shorter runs of
category 5 wires up to 100 ft. it is also possible to use the optional 36 watts
per channel amplifiers in the rooms.

Figure 1

There are some other products on the market that provide a similar functional
solution but users are advised to look at the specifications. Most of them do
not publish any specifications on the product since their units do not deliver
more than three or four watts of power, and the frequency response, dynamic
range and signal to noise ratio are not high-fidelity. Manufacturers that
produce quality products always publish their product specifications to help the
user in making a decision. Users are advised to ask for printed technical
specifications or a limited time money-back guarantee before selecting products
from any manufacturer. PADS™ solves the problem of a single source
distribution throughout the home but there may be applications where a
multi-source, multi-zone implementation is desired.

The multi-source, multi-zone design of DMS™ (Distributed Music System) is
based on the TPA™ (Twisted Pair Audio) and SAA™ (Stereo Audio Amplifier)
components with a digital pre-amplifier for volume control. A typical
implementation for multi-source, multi-zone music distribution is shown in
Figure 2.

Figure 2

The DMS4.4™ features a built-in TV/CATV/FM tuner as its first source. Three
additional sources can be connected to the unit. As shown in the figure, there
are two sources (CD jukebox and DSS audio receiver) in the network connection
closet. Also a remote source such as an office PC with MP3 player can be
connected via a TPA transmitter and receiver pair. Using the TPA™ line-level
stereo audio transmitter, signals are transmitted over standard category 5
cables to the remote room. The SuperTranZ™ circuit incorporated in the TPA™
transmitters and receivers eliminates ground loops and noise pick up, and
provides a clean signal in the remote room. The signals into the DMS4.4™ will
have a signal-to-noise ratio in excess of 96 dB and a 20Khz bandwidth. Thus the
signal quality is maintained throughout the installation.

In each of the bedrooms, the In-Wall keypad and amplifier fits in a single
gang box. The keypads also offer direct keypad access to the source selection.
Source control using an Infra-Red remote control is made possible with the
built-in IR re-transmission. Also all the keypads are networked together on an
RS-485 serial data bus along with the DMS4.4™ main unit so integration with a
home automation or PC based control system is simple. In this set-up one
category 5 cable is used for the audio, IR and control signals for the
amplifiers and keypads. Another category 5 cable in the existing structured
wiring bundle can be used for connecting to the central power supply unit. For
new construction, it is recommended that an 18/2 AWG wire be used for the power
in the wiring bundle. Having a heavier gauge wire for the power opens up the
possibility to upgrade to a 36 watts per channel or 48 watts per channel in-wall
amplifier keypad.

The DSP based high performance and high efficiency amplifiers in the room
produce big luxurious sound, yet fit into a standard size junction box! The
small, powerful package delivers true high fidelity performance that actually
rivals the sound quality of large amplifiers. It consists of two separate
mono-block amplifiers that provide extremely clean state-of-the-art power
producing unexpected sound depth and musical clarity. The advanced protection
circuitry of the amplifiers guards against system damage from overload,
over-temperature, or short circuits. This makes them almost indestructible. The
amplifiers provide clean 24 watts per channel with a power bandwidth of 100KHz
and distortion less than 0.02% in the listening range.

Each room is capable of listening to and controlling a different source to
create complete four sources, four zone distributed music system. The system can
be expanded to additional 4 more zones by adding another DMS4.4™ unit in the
network connection center.

There may be products on the market from other manufacturers that appear to
operate similarly but once again the user is advised to check for the
specifications. A low output of 3 or 4 watts per channel will sound terrible
even for background music.

Besides the salient features of the DMS™ system discussed here, it is
possible to upgrade the implementation to include full DVD quality video and
Infra-red remote control communications on the same category 5 cable using the
advanced CATS™ products which are not discussed here. It can be envisioned
that in the future the same category 5 cable can be used to carry Dolby Digital™,
DTS™ or other multi-channel formats as well as HDTV signals using Pragmatics'
patent pending technologies. More information can be obtained from the web site www.wireless-experts.com
.

In summary, it can be seen that the structured wiring can be re-utilized
properly for a high quality distributed music system. The plug-and-play
simplicity of the PADS™ and DMS™, not only benefits the professional
installers in completing their installations with speed and performance but also
enables the do-it-yourselfers to have a high quality music distribution system
installed by themselves without any problems. Also the new homeowners in recent
years who have been lucky enough to have their homes pre-wired with structured
wiring can benefit from the ease and simplicity of this design. They can add
high quality of music to their homes without any additional wiring. Conclusion

The DMS™ represents a major breakthrough in high quality music
distribution. It solves problems that have not been addressed by the traditional
methods for over four decades. The superior signal quality level, the
versatility of the system, and the complete avoidance of problems which plague
traditional methods, make DMS™ the best overall approach to whole house music
distribution.

The DMS™ has been successfully installed in a variety of commercial
applications including music distribution at a resort and also residential
applications involving connections of MP3 music from a personal computer in the
home office to the main audio system in the family room.

About the Company

Pragmatic Communications Systems, Inc., is a Silicon valley based company
established in 1994 to design, develop, and produce a variety of innovative
products for wireless audio, video, and data communications. The majority of
company's products until 1997 were primarily designed for industrial and
commercial applications. The success of these products has led to a strong and
dynamic technology base, which has been applied to new generation of products
such as the PADS™ and DMS™ as described in this article, and others like the
CATS™, TrueMusic™ wireless hi-fi system and TrueView™ wireless video
system. The company's philosophy is to use its technologies to solve problems
that have gone unresolved for decades. For more information: Pragmatic
Communications Systems, Inc. 544 E. Weddell Drive, Unit 8 Sunnyvale, CA 94089
USA Tel. (408) 542 0330 Fax (408) 542 0339 Email: sales@wireless-experts.com
Web: www.wireless-experts.com

Author's biography

Prasanna M. Shah is the Chief Pragmatist and Thinker at Pragmatic
Communications Systems, Inc. He earned his M.S. degree in Electrical Engineering
from Stanford University and B.S. degree in Electrical Engineering from Santa
Clara University, Santa Clara, CA. He has more than two decades of experience
working on semiconductors for analog and digital audio, video, cellular
telephones, wireless communications, fiber optic communications, data
communications, data acquisition and industrial controls in the Silicon Valley.
He holds patents on power line and wireless data communications, and several
patents pending on audio, video and wireless multimedia systems. An avid
audiophile and music lover, in his free time, he likes to apply his pragmatic
thinking to solve complex problems.